Memory device and recording/reproducing apparatus using the same

ABSTRACT

The present invention provides a memory card ( 1 ) using a write-once memory IC ( 17 ), such as PROM. In this memory IC ( 17 ), an entity data recording area, where the entity data of a file is recorded, and a management data recording area, where management data for supervising the recorded files in accordance with a hierarchical directory structure is recorded, are formed at the outset. In the management data recording area, a file entry specifying the files recorded in the memory card ( 1 ), a root entry specifying the uppermost order directory in the hierarchical directory structure and a sub-entry specifying sub-directories in the hierarchical directory structure, are recorded as management data in association with the files, root directory and the sub-directories generated, respectively.

TECHNICAL FIELD

[0001] This invention relates to a memory device including a recordingmedium capable of writing data only once on the bit basis, a recordingand/or reproducing apparatus employing this memory device, and to a filemanagement method for supervising the files recorded in the memorydevice.

[0002] This application claims priority of Japanese Patent ApplicationNo. 2001-392453, filed on Dec. 25, 2001, the entirety of which isincorporated by reference herein.

BACKGROUND ART

[0003] Up to now, as an external storage device for host equipment, suchas portable information terminals, desk top computers, notebookcomputes, audio appliances or household electrical appliances, a cardtype small-sized removable IC memory, detachably mounted to theseequipment and having enclosed therein a semiconductor memory, has beenused.

[0004] This sort of the memory device has a nonvolatile semiconductormemory (IC memory), such as a flash memory, enclosed therein. In thissemiconductor memory, various digital data, such as still image data,moving picture data, speech data or music data, are stored. The flashmemory is a rewritable memory for repeatedly writing or erasing data.Thus, for the memory device, having enclosed therein the flash memory, afile management system of a routine hierarchical directory structure,exemplified by MS-DOS (trademark) format, premised on the use of therewritable disc medium, may be used.

[0005] Meanwhile, the flash memory is a relatively costly device. Thus,by using a write-once type non-volatile semiconductor memory, such asPROM (programmable read-only memory), which is less costly than theflash memory, as a data storage device, a memory device can befabricated at a lower cost.

[0006] If the write-once type non-volatile semiconductor memory is usedin this manner as the data storage device for the memory device, it ismore desirable for convenience to the user to supervise the files by thehierarchical directory structure, such as the MS-DOS (trademark) format,as in the case of the rewritable memory device employing the flashmemory.

[0007] With the memory device, employing the write-once typesemiconductor memory, as data storage device, it is not possible toerase the recorded entity data. For convenience to the user, the filesetc. preferably can be pseudo-erased on the file management system.

[0008] Even in the memory device employing the write-once typesemiconductor memory, as the data storage device, the readout processingitself is the same as that in the memory device employing the rewritablesemiconductor memory. Thus, for convenience to the user, the physicalstructure and the file management system compatible with a conventionalIC memory device, having the rewritable semiconductor memory, isdesirable, insofar as data readout is concerned.

DISCLOSURE OF THE INVENTION

[0009] It is therefore an object of the present invention to provide anovel memory device whereby the problems inherent in the above-describedconventional memory device may be resolved, and a recording and/orreproducing apparatus employing this memory device.

[0010] It is a further object of the present invention to provide amemory device employing a write-once type memory as a data storagemedium and which is able to supervise files by a hierarchical directorystructure, a file management method for this memory device, and a datarecording and/or reproducing apparatus for recording and/or reproducingdata for this memory device.

[0011] The present invention provides a memory device having a recordingmedium on which data can be written only once on the bit basis and whichincludes an entity data recording area for recording entity data of afile and a management data recording area for recording management datasupervising the recorded files by a hierarchical directory structure. Inthe management data recording area, a file entry for specifying a filerecorded on the recording medium, a root entry for specifying theuppermost order directory in the hierarchical directory structure and asub-entry for specifying a sub-directory in the hierarchical directorystructure, are recorded as the management data in association with thefile(s), root directory and the sub-directory generated, respectively.The name of the file specified, the information identifying the rootentry or the sub-entry specifying the parent directory of the file, andthe information for identifying a recording position of the entity dataof the file, are included in the file entry. The name of thesub-directory specified and the information identifying the root entryor the sub-entry specifying the parent directory of the subdirectory areincluded in the sub-entry.

[0012] The present invention also provides a file management method fora recording medium on which data can be written only once on the bitbasis, comprising dividing a data recording area on the recording mediuminto an entity data recording area for recording entity data of a fileand a management data recording area for recording management datasupervising the recorded files by a hierarchical directory structure,supervising the so divided data recording area, recording a file entry,specifying a file recorded on a recording medium, a root entry forspecifying the uppermost order directory in the hierarchical directorystructure and a sub-entry for specifying a sub-directory in thehierarchical directory structure, in the management data recording area,in association with the file, root directory and the sub-directorygenerated, respectively, including the name of the file specified, theinformation identifying the root entry or the sub-entry specifying aparent directory of the file and the information for identifying arecorded position of the entity data of the file in the file entry, andincluding the name of the sub-directory specified and the informationidentifying the root entry or the sub-entry specifying a parentdirectory of the sub-directory in the sub-entry.

[0013] The present invention also provides a recording and/orreproducing apparatus having a recording and/or reproducing unit forrecording and/or reproducing a file for a memory device including arecording medium on which data can be written only once on the bit basisand which is provided with an entity data recording area for recordingentity data of the files and a management data recording area forrecording management data supervising the recorded files in accordancewith a hierarchical directory structure. The recording and/orreproducing unit, in recording data, records the entity data of thefiles in the entity data recording area, while recording a file entry,specifying the files recorded on a recording medium, a root entry forspecifying the uppermost order directory in the hierarchical directorystructure and a sub-entry for specifying a sub-directory in thehierarchical directory structure, in the management data recording area,in association with the file, root directory and the sub-directorygenerated, respectively, including the name of the file specified, theinformation identifying the root entry or the sub-entry specifying aparent directory of the file and the information for identifying arecording position of the entity data of the file, in the file entry,and including the name of the sub-directory specified and theinformation identifying the root entry or the sub-entry specifying theparent directory of the sub-directory, in the sub-entry. The recordingand/or reproducing unit in reproducing data references the file entry,root entry and the sub-entry, recorded in the management data recordingarea, and supervises the hierarchical directory structure of therecorded files, based on the names indicated in these entries and theinformation identifying the root entry or the sub-entry specifying theparent directory while referencing the file entry, root entry and thesub-entry, recorded in the management data recording area, and readingout entity data of a predetermined file from the entity data recordingarea based on the information identifying the recording position of theentity data of the file indicated in these entries.

[0014] The present invention also provides a write-once memory devicehaving a recording medium on which data can be written only once on thebit basis and which includes an entity data recording area where entitydata of a file is recorded and a management data recording area wheremanagement data for the write-once format for supervising the files inaccordance with a hierarchical directory structure is recorded. A fileentry, specifying a file recorded on a recording medium, a root entryfor specifying the uppermost order directory in the hierarchicaldirectory structure and a sub-entry for specifying a sub-directory inthe hierarchical directory structure, are recorded in the managementdata recording area, in association with the file, root directory andthe sub-directory generated, respectively. The name of the filespecified, the information identifying the root entry or the sub-entryspecifying a parent directory of the file and the information foridentifying a recorded position of the entity data of the file(s) areincluded in the file entry. The name of the sub-directory specified andthe information identifying the root entry or the sub-entry specifying aparent directory of the sub-directory are included in the sub-entry. Thephysical format of the entity data recording area is identified with thephysical format of an effective area of a recording medium of arewritable memory device capable of re-writing data a plural number oftimes and having the effective area and a reserve area for datasubstitution, the effective area being an area where entity data isrecorded. The physical format of the management data recording area isidentified with the physical format of the reserve area in therewritable memory device.

[0015] The present invention also provides a file management method fora write-once recording medium on which data can be written only once onthe bit basis, comprising dividing a recording area of the write-oncerecording medium into an entity data recording area for recording entitydata of files and a management data recording area for recordingmanagement data for the write-once format supervising the recorded filesin accordance with a hierarchical directory structure, supervising theso divided data recording area, recording a file entry, specifying afile recorded on the recording medium, a root entry for specifying theuppermost order directory in the hierarchical directory structure and asub-entry for specifying a sub-directory in the hierarchical directorystructure, as management data for the write-once format, in themanagement data recording area, in association with the file, rootdirectory and the sub-directory generated, respectively, including thename of the file specified, the information identifying the root entryor the sub-entry specifying a parent directory of the file and theinformation for identifying a recorded position of the entity data ofthe file, in the file entry, and including the name of the sub-directoryspecified and the information identifying the root entry or thesub-entry specifying the parent directory of the sub-directory, in thesub-entry, supervising the entity data recording area as being of thesame physical format as the physical format of an effective area of arewritable recording medium capable of rewriting data a plural number oftimes, and supervising the management data recording area as being ofthe same physical format as that of the reserve area in the rewritablerecording medium. The rewritable recording medium has a reserve area fordata substitution in addition to the effective area, the effective areabeing an area where entity data are recorded.

[0016] The present invention also provides a recording and/orreproducing apparatus having a recording and/or reproducing unit forrecording and/or reproducing a file recorded on a one-time memory deviceincluding a recording medium capable of rewriting data on the bit basis,the recording medium having an entity data recording area for recordingentity data of the files and a recording area for management data for awrite-once format for recording management data supervising the files inaccordance with a hierarchical directory structure. The recording and/orreproducing unit records a file entry for specifying a file recorded onthe recording medium, a root entry specifying an uppermost orderdirectory in the hierarchical directory structure and a sub-entryspecifying a sub-directory in the hierarchical directory structure, asthe management data for the write-once format, in association with thefile, root directory and the sub-directory generated, respectively, inthe management data recording area, includes the name of the filespecified, the information identifying the root entry or thesub-directory specifying a parent directory of the file and theinformation identifying the recording position of entity data of thefile, in the file entry, includes the name of the sub-directoryspecified and the information identifying the root entry or thesub-directory specifying a parent directory of the sub-directory, in thesub-entry, supervises the entity data recording area by identifying thephysical format of the entity data recording area with the physicalformat of an effective area of a rewritable memory device capable ofre-writing data a plurality of number of times, and supervises themanagement data recording area by identifying the physical format of themanagement data recording area with the physical format of the reservearea in the rewritable memory device. The rewritable memory device hasthe effective area and a reserve area for data substitution, theeffective area being an area where entity data is recorded. Further, therecording and/or reproducing unit supervises the management data byidentifying the physical format of the management data recording areawith the physical format of the reserve area in the rewritable memorydevice.

[0017] Other objects, features and advantages of the present inventionwill become more apparent from reading the embodiments of the presentinvention as shown in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a perspective view showing a memory card embodying thepresent invention and a host equipment employing this memory card.

[0019]FIG. 2 shows the structure of a memory cell of the memory card.

[0020]FIG. 3 is a perspective view showing the memory card from itsfront side.

[0021]FIG. 4 is a perspective view showing the memory card from itsreverse side.

[0022]FIG. 5 illustrates a terminal structure of the memory card.

[0023]FIG. 6 is a block diagram showing an internal circuit of thememory card.

[0024]FIG. 7 illustrates an interfacing structure of the memory card.

[0025]FIG. 8 shows the relationship between a segment and a block andthe relationship between the physical block number and the logicaladdress as defined on the physical format of the memory card.

[0026]FIG. 9 illustrates a boot area and a user area as defined on thephysical format of the memory card.

[0027]FIG. 10 illustrates a page as defined on the physical format ofthe memory card.

[0028]FIG. 11 illustrates a preliminary block management number asdefined on the physical format of the memory card.

[0029]FIG. 12 illustrates an entry page as defined on the physicalformat of the memory card.

[0030]FIGS. 13A to 13F illustrate a species-based field image of theentry page.

[0031]FIG. 14 shows an illustrative directory structure of for example afile recorded on a memory card.

[0032]FIG. 15 shows a recording image of the entry page in case ofrecording a file by the directory structure shown in FIG. 14.

[0033]FIG. 16 shows the directory structure after deleting an optionalfile from the file of the directory structure shown in FIG. 14.

[0034]FIG. 17 shows a recording image of the entry page in case ofdeletion of the file shown in FIG. 16.

[0035]FIG. 18 is a flowchart showing the processing sequence of sessionclosing processing.

[0036]FIG. 19 shows the directory structure of the file recorded in thememory card at the time of the first session closure processing.

[0037]FIG. 20 shows a recording image of the entry page following thefirst session closure processing.

[0038]FIG. 21 shows a recording image of the data recording areafollowing the first session closure processing.

[0039]FIG. 22 shows the directory structure of a file recorded in asmall-sized IC memory at the time of a second session closureprocessing.

[0040]FIG. 23 shows a recording image of the entry page following thesecond session closure processing.

[0041]FIG. 24 shows a recording image of the data recording areafollowing the second session closure processing.

[0042]FIG. 25 shows the directory structure of a file recorded in asmall-sized IC memory at the time of a third session closure processing.

[0043]FIG. 26 shows a recording image of the entry page following thethird session closure processing.

[0044]FIG. 27 shows a recording image of the data recording areafollowing the third session closure processing.

BEST MODE FOR CARRYING OUT THE INVENTION

[0045] The present invention is now explained taking an example ofapplying a memory device of the present invention to a small-sizedcard-shaped IC memory device, and an example of applying the presentinvention to a data processing apparatus employing this memory card asan external storage device.

[0046] The data processing apparatus, in which the memory card embodyingthe present invention is used as an external storage medium, may beexemplified by a desk top computer, a notebook computer, a portabletelephone set, an audio appliance or a domestic electrical equipment.

[0047] In the following explanation, the data processing apparatus,employing the memory card, embodying the present invention, is termed ahost equipment.

[0048] Referring first to FIG. 1, the schematics of a memory card 1according to the present invention and a host equipment 2 employing thismemory card as an external storage medium, are explained.

[0049] The memory card 1 according to the present invention has enclosedtherein a non-volatile memory, which allows data writing only once, thatis a write once type semiconductor memory, referred to below aswrite-once memory, as a data storage medium. The memory card 1 is usedin a state it is inserted via an insertion/ejection opening 3, providedin the host equipment 2, as shown in FIG. 1. The memory card 1 mayoptionally be inserted or ejected at the insertion/ejection opening 3 bythe user. Thus, the memory card 1, so far inserted in a given hostequipment, may be extracted and inserted into another host equipment.That is, the present memory card 1 may be used for exchanging databetween different host equipment.

[0050] The write-once memory, provided within the memory card 1, is aPROM (programmable read only memory) employing a diode destruction typememory cell capable of writing data on the bit basis. This diodedestruction type memory cell is made up by pn diodes D1, D2, connectedin series in opposite directions to each other across a line and acolumn, as shown in FIG. 2. In the diode destruction type memory cell,the value of the stored bit is inverted by reverse-biasing and therebydestructing one of the pn diodes. Meanwhile, for the write-once memory,used for the memory card 1, a so-called fuse type or a floating gatePROM may also be used in place of the diode destruction type cell.

[0051] In the write-once memory, used for the memory card 1, the bitvalue held by each memory cell is “1” (high) in an initial state. Thatis, if no data has been written, “1” is read out from each memory cell.If “0” (low) is written in this initial state memory cell, the pn diodeis destructed, so that the value stored in the memory cell is changed to“0”. If once the stored value of the memory cell is “0”, the storedvalue is not changed if “1” or “0” is subsequently written in the memorycell, such that the state of “0” is maintained. If, on the other hand,“1” is written in the memory cell in the initial state, the stored valuein the memory cell continues to be “1” . Since the diode is notdestructed in this state, “0” can subsequently be written in the memorycell.

[0052] In contradistinction from the memory card 1 of the presentinvention, described above, the conventionally proposed memory card hasenclosed therein a non-volatile semiconductor memory, termed a flashmemory, capable of being rewritten a number of times, as a data storagedevice. The memory card 1 according to the present invention isconfigured so as to be compatible with the conventional memory cardemploying the flash memory as to appearance, connection terminal, ordata transfer interface with the host equipment. The memory card 1according to the present invention can be used loaded on a hostequipment employing the conventional memory card employing in turn aflash memory. Moreover, the host equipment 2, capable of employing thememory card 1 of the present invention, may use the conventional memorycard, employing the flash memory, as an external storage medium. Thatis, the memory card according to the present invention is compatiblewith the conventional memory card, employing the flash memory, insofaras the interface is concerned.

[0053] The memory card according to the present invention is nowexplained in detail, as it is compared as necessary to the conventionalmemory card employing the flash memory.

[0054] If, in the following explanation, it becomes necessary to clarifythe difference between the conventional memory card employing the flashmemory and the memory card according to the present invention, theconventional memory card employing the flash memory and the associatedhost equipment are occasionally referred to as Ver1, while the memorycard according to the present invention and the associated hostequipment are occasionally referred to as Ver2.

[0055] The memory card 1 according to the present invention is formed asa substantially rectangular thin sheet with a longitudinal length L₁equal to 50 mm, a width W₁ equal to 21.45 mm and a thickness D₁ equal to2.8 mm, as shown in FIG. 3. The memory card 1 has one surface as a frontside 1 a and the opposite side surface as a reverse side 1 b. On thereverse side 1 b towards one longitudinal end of the memory card 1,there is provided a set of connection terminals 4, made up by ten planarelectrodes, as shown in FIG. 4. The respective electrodes, constitutingthe set of connection terminals 4, are provided side-by-side along thewidth-wise direction of the memory card 1. Between the neighboringelectrodes, there are formed partitioning pieces 5 upstanding from thereverse side 1 b. The partitioning pieces 5 are used for preventingconnection terminals connected to the respective electrodes fromcontacting with other electrodes. A slide switch 6 for prohibitinginadvertent erasure is mounted centrally of the longitudinal end of thereverse side 1 b of the memory card 1, as shown in FIG. 4.

[0056] The host equipment 2, on which is loaded the above-describedmemory card 1, is provided with an insertion/ejection opening 3 forinserting/ejecting the memory card 1. The insertion/ejection opening 3is formed on the front side of the host equipment 2 as an opening of awidth and a thickness corresponding to the width W₁ and the thickness D₁of the memory card 1, respectively, as shown in FIG. 1. The memory card1, inserted into the host equipment 2 via the insertion/ejection opening3, is held on the host equipment 2 against inadvertent descent by therespective electrodes of the set of connection terminals 4 beingconnected to connection terminal provided on the host equipment 2.Meanwhile, the connection terminals of the host equipment 2 are providedwith ten terminals for mating with the number of the electrodes of theset of connection terminals 4 provided on the memory card 1 loadedthereon.

[0057] The memory card 1 of the present invention is loaded through theinsertion/ejection opening 3 on the host equipment 2, via one endprovided with the set of connection terminals 4 as an inserting end,along the direction indicated by arrow X in FIG. 3 as the insertingdirection. With the memory card 1 connected to the host equipment 2,signal exchange becomes possible by connection of the contacts of theconnection terminals of the host equipment 2 with the respectiveelectrodes of the set of connection terminals 4.

[0058] The functions of the ten terminals of the set of connectionterminals 4, provided on the memory card 1 according to the presentinvention, is now explained with reference to FIG. 5.

[0059] The first terminal 4 a of the set of connection terminals 4 is aVSS terminal to which is connected VSS (reference voltage of 0 volt).The first terminal 4 a, as the VSS terminal, interconnects the ground ofthe host equipment 2 and the ground of the memory card 1 to match the 0volt reference voltage of the host equipment 2 to that of the memorycard 1.

[0060] The second terminal 4 b forms a BS terminal such that a bus statesignal is input from the host equipment 2 to the memory card 1.

[0061] The third terminal 4 c forms the VCC terminal to supply thesource voltage (VCC) from the host equipment 2 to the memory card 1. Thesource voltage which enables the operation of the memory card 1 is 2.7to 3.6V such that the voltage in this voltage range is supplied.

[0062] The fourth terminal 4 d forms a SDIO terminal for input/output ofserial data signals transferred between the memory card 1 and the hostequipment 2.

[0063] The fifth terminal 4 e is a spare terminal for which noparticular function is allocated.

[0064] The sixth terminal 4 f forms an INS terminal and is used forinsertion/extraction check for the host equipment 2 to check whether ornot the memory card 1 has been inserted into the insertion/ejectionopening 3.

[0065] The seventh terminal 4 g is a spare terminal for which noparticular function is allocated.

[0066] The eighth terminal 4 h forms an SCLK terminal which allows theinputting of clock signals of serial data, transmitted between thememory card 1 and the host equipment 2, from the host equipment to thememory card.

[0067] The ninth terminal 4 i forms a VCC terminal which allows thesource voltage (VCC) to be supplied from the host equipment to thememory card. The ninth terminal 4 i is connected to the third terminal 4c within the inside of the memory card 1.

[0068] The tenth terminal 4 j is used as a VSS terminal and connects theground of the host equipment 2 to the ground of the memory card 1 toestablish the matching of the 0-volt reference potential between thehost equipment 2 and the memory card 1. The tenth terminal 4 j isconnected to the first terminal 4 a, similarly used as a VSS terminal,within the inside of the memory card 1.

[0069] Meanwhile, the terminal structure of the memory card 1 of thepresent invention, the shape of the insertion/ejection opening 3 of thehost equipment 2 to which the memory card 1 is loaded (Ver2) and thestructure of the connection terminal are similar in structure to thoseof the conventional memory card employing the flash memory and the hostequipment employing the conventional memory card (Ver1), in order toassure mechanical compatibility.

[0070] The internal circuit of the memory card 1 according to thepresent invention is hereinafter explained.

[0071] Referring to FIG. 6, the memory card 1 according to the presentinvention includes an interfacing circuit (I/F) 12, a register circuit13, a data buffer circuit 14, an ECC circuit 15, a memory I/F sequencecircuit 16, a write-once memory 17 and an oscillation control circuit18.

[0072] The I/F circuit 12 transfers data between it and the hostequipment 2, using the three-wire half-duplex serial protocol.

[0073] The register circuit 13 is a circuit for storage of, for example,a command transferred from the host equipment, the inner state in thememory card 1, addresses of data to be accessed, various parametersneeded in executing a command, the file management information in thewrite-once memory 17 and so forth. The information stored in theregister circuit 13 is accessed from the memory I/F sequence circuit 16or accessed by issuing a predetermined command from the host equipment2.

[0074] The data buffer circuit 14 is a memory circuit for transientlyholding data written in the write-once memory 17 and data read out fromthe write-once memory 17. The data buffer circuit 14 has a data capacitycorresponding to a predetermined data writing unit (512 bytes which is apage size as later explained).

[0075] The ECC circuit 15 adds an error correction code (ECC) to thedata written in the write-once memory 17. The ECC circuit 15 correctsdata read out from the write-once memory 17 for errors, based on theerror correction code appended to data read out from the write-oncememory 17. For example, three bytes of the error correction code areappended to a data unit of 512 bytes.

[0076] The memory I/F sequence circuit 16 controls data exchange betweenthe data buffer circuit 14 and the write-once memory 17 in accordancewith the various information or the commands stored in the registercircuit 13.

[0077] The write-once memory 17 is a semiconductor memory capable ofre-writing stored data only once, as explained previously.

[0078] The oscillation control circuit 18 generates operating clockswithin the present memory card 1.

[0079] The memory card 1, constructed as described above, effects datawriting, data readout or data erasure (erasure on the file system) inaccordance with for example the various commands sent from for examplethe host equipment 2 over an interface.

[0080] The system configuration, providing for interfacing between thememory card 1 and the host equipment 2, is hereinafter explained.

[0081]FIG. 7 shows the functional structure of the interface for datatransmission between the memory card 1 and the host equipment 2according to the present invention.

[0082] The host equipment 2 includes a file manager 31, a TPC interface32 and a serial interface 33. The memory card 1 includes a serialinterface 35, a register 37, a data buffer 38, a memory controller 39and a memory 40.

[0083] The file manager 31 supervises a file stored in the memory card1, and a file stored in other mediums of the host equipment.

[0084] The TPC interface 32 becomes a lower layer of the file manager31. The TPC interface 32 accesses the register 37 and the data buffer 38in the memory card 1 by a command peculiar to the interface of thepresent memory card 1 (TPC: Transfer Protocol Command).

[0085] The serial interfaces 33, 35 become lower layers of the TPCinterface and represent physical hierarchies of the present interfacingsystem. The serial interfaces 33, 35 effect data transfer in accordancewith the three wire half duplex serial protocol transmitting threesignals, namely 1-bit serial data, clock signals and bus state signals.

[0086] The register 37 stores commands transmitted from the host, theinner states of the memory card, memory data addresses, variousparameters needed in executing the commands, the file managementinformation in the memory and so forth.

[0087] The data buffer 38 is a buffer area in which data written in thememory 40 or data read out from the memory 40 is to be storedtransiently.

[0088] The memory controller 39 controls the data exchange between thedata buffer 38 and the memory 40, to read out and write data, inaccordance with the various information and commands stored in theregister circuit 13.

[0089] The memory 40 is a memory area for data and is rendered a virtualmemory by the memory controller 39 as a unique model.

[0090] The host equipment 2 and the memory card 1, constructed asdescribed above, is able to transfer data, stored in other mediumssupervised by the file manager 31 over a serial interface to the memory40, and to transfer the data stored in the memory 40 over the serialinterface to other mediums, supervised over the serial interface by thefile manager.

[0091] Meanwhile, the interface structure and the data transfer protocolof the memory card 1 according to the present invention (Ver2) are thesame as and compatible with the conventional memory card employing theflash memory (Ver1).

[0092] The physical format of the data storage area of the memory card 1according to the present invention is now explained.

[0093] The data capacity of the memory card 1 (data that can be storedby the memory card 1) is e.g. 16 Mbytes, 32 Mbytes, 64 Mbytes or 128Mbytes.

[0094] The memory card 1 defines a data unit termed a block and the datastorage area is physically supervised in terms of this block as a unit.The one-block data size is e.g. 16 Kbytes. Thus, with the memory cardwith 16 Mbyte, 32 Mbyte, 64 Mbyte or with 128 Mbyte, the total number ofblocks is 1024, 2048, 4096 or 8192, respectively. This block is the sameas an erasure block in a conventional memory card employing the flashmemory.

[0095] The block is classed into an effective block and a spare block.The effective block is a block in which deferred reject substitutiondata and data for file management are recorded. The total number ofspare blocks in one memory card 1 is 31, 63, 127 and 255 for memorycards with 16 Mbyte, 32 Mbyte, 64 Mbyte and 128 Mbyte, respectively.

[0096] In each block, the physical block number, specifying the storagelocation of the block, is set. This physical block number is a serialnumber, beginning from 0, without regard to whether a block in questionis an effective block or a spare block.

[0097] A logical address is recorded in each block. This logical blockis written in a predetermined area in the block. For the effectiveblock, the logical address is prerecorded e.g. at the time of shipmentfrom a plant, whereas, for the spare block, no logical address isrecorded at the time of shipment. If malfunction has occurred later in ablock of a specified logical address, the logical address of themalfunctioning block is written in the non-recorded spare block by wayof substitution. That is, the logical address as well as the physicalblock number is pre-set for the effective block, whereas, for the spareblock, the logical address is set following shipment from the plant.

[0098] In the memory card 1, a set of 512 blocks is defined as asegment. The segment number is set by serial numbers beginning fromzero. Each segment is made up by effective blocks and spare blocks. Thenumber of effective blocks of a 0 segment is 495, with the number of thespare blocks being 15. The number of effective blocks of each of theremaining segments is 496, with the number of the spare blocks being 16.The smaller number of the effective blocks and that of the spare blocksin the 0 segment is ascribable to the provision of a boot block as laterexplained.

[0099] The relationship between the segment and the block and therelationship between the physical block number and the logical address,described above, are as shown in FIG. 8.

[0100] The two leading blocks of the 0 segment, that is the blocks withthe physical block numbers of “0” and “1”, is a boot area, as shown inFIG. 9. It is noted that no logical address is recorded for theseblocks. The boot area is an area in which data is initially read in whenthe host equipment has booted the memory card 1. In the blocks of thisboot area are recorded the information and the attribute pertinent tothe memory card. The area in which the boot has been recorded is termeda boot area, while the other area is termed a user area.

[0101] Each block is made up by 32 pages, as shown in FIG. 10. The pageis a unit made up by a data area of 512 bytes and an extra data area. Inthe data area, data entity, that is the entity data and the managementdata of the file, are recorded.

[0102] The extra data area is made up by a 1 byte (8 bits) of anoverwrite flag area, a 1-byte of a management flag area, 2-bytes of thelogical address area, 5 bytes of a format reserve area, a first ECC areaand a second ECC area, beginning from the leading end.

[0103] In the overwrite flag area, a block status, a page status, anupdate status and a data use status are recorded in the first bit,second and third bits, fourth bit and in the fifth bit, beginning fromthe leading end, respectively. The sixth to eighth bits are a reservearea.

[0104] The block status is a 1-bit discriminating flag specifyingwhether or not the block containing the page is malfunctioning, orwhether or not the data recorded in the block containing the page hasbeen deleted. The block status with a value of “0” indicates that theblock is in the malfunctioning state or in the data-deleted state, whilethat with a value of “1” indicates that the block is in an accessiblestate. This block status is “1” in the initial state such as at the timeof shipment from the plant. If the block is malfunctioning, or if thedata written in the block is pseudo-erased on the file managementsystem, the block status value is rewritten to “0”.

[0105] The page status is a two-bit discrimination flag indicating thestatus of occurrence of uncorrectable errors on the page basis. If thevalue of the page status is “00”, it indicates that the data in the pageis suffering from errors correctable by ECC, whereas, if the value ofthe page status is “01”, it indicates that the data in the page issuffering from errors uncorrectable by ECC and, if the value of the pagestatus is “11”, it indicates that the no errors are occurring in thedata within the page.

[0106] The update status is a 1-bit flag indicating the update state ofthe block containing the page. The update state having a value of “0”indicates that the data of the block is in the recorded state or thatthe data in the block is being updated, while the update state having avalue of “1” indicates that no data has been recorded in the block.

[0107] The data use status is a 1-bit discrimination flag indicatingthat data has been recorded in the block containing the page and thatthe block is already being used. The data use status having a value of“0” indicates that data has already been recorded in the block, whilethe data use status having a value of “1” indicates that no data hasbeen recorded in the page.

[0108] In the management flag, there are included a system bitindicating whether the block containing the page is the boot block orother blocks, a copy limiting bit for the page, an access limiting bitfor the page, and so forth.

[0109] In the logical address, the address information for the block isrecorded.

[0110] The first ECC is an error correction code for the one-bytemanagement flag, a two-byte logical address and an error correction codefor the five-byte format reserve.

[0111] The second ECC is an error correction code for the 512-byte pagedata.

[0112] The physical format of the memory card 1 according to the presentinvention has the following configuration.

[0113] When compared to the physical format of the conventional memorycard employing the flash memory and which can be rewritten a pluralnumber of times, the physical format of the memory card 1 has the samebasic configuration as the physical format of the conventional memorycard. However, the physical format of the memory card 1 according to thepresent invention differs from the physical format of the conventionalmemory card in the fact that the data use status has been defined in thephysical format of the memory card 1. That is, in the present memorycard 1, the fifth bit in the overwrite flag area is a data use status,whereas, in the conventional memory card employing the flash memory andwhich can be rewritten a plural number of times, the fifth bit of theoverwrite flag area is a reserve.

[0114] With the memory card 1 of the present invention, in which thedata use status and the block status are defined by the physical formatas described above, it is possible to distinguish three states, that isa state in which no data has been recorded in the block, a state inwhich data has been recorded in the block and a state in which datarecorded in the block has been erased. Thus, even with the write-oncetype memory card 1, the data erasure state can be pseudo-managed as longas the file management system is concerned.

[0115] In the memory card 1, in which the new data use flag is definedin the reserve area of the conventional memory card employing the flashmemory and which can be rewritten a plural number of times, data readoutcompatibility may be afforded as long as the physical format isconcerned. That is, the contents of the data use status, defined onlyfor the present memory card 1, do not affect the conventional memorycard.

[0116] Among the information recorded in an extra data area in the page,there are the information indicating contents inherent from block toblock and the information indicating the contents inherent from page topage. The block status, update status, data use status and the logicaladdress represent the information indicating the contents inherent fromblock to block. The page status and the management flag represent theinformation indicating the contents inherent from page to page. That is,the information contents of the block status, update status, data usestatus and the logical address remain the same for the totality of pagesin the same block. Thus, these information may be recorded only in theleading page in the block.

[0117] Meanwhile, as long as the physical format is concerned, thememory card 1 of the present invention is not provided with an area inwhich to record a table correlating the physical block number with thelogical addresses. Thus, in booting the memory card 1, the hostequipment accesses the leading pages of all blocks to detect logicaladdresses to formulate a table correlating the physical address numberswith the logical addresses.

[0118] The logical format of the memory card 1 according to the presentinvention is now explained.

[0119] The conventional memory card, employing the flash memory, andwhich can be rewritten a plural number of times, uses the MS-DOScompatible format as the logical format. The MS-DOS compatible format isa file system supervising data files recorded on a recording medium inaccordance with a hierarchical directory structure. The MS-DOScompatible format in supervising the recorded data provides for arecording and/or reproducing unit (cluster) for the recording medium.With the conventional memory card, the data recording and/or reproducingunit (cluster) provided for by the MS-DOS is a block.

[0120] On the other hand, the write-once type memory card 1 of thepresent invention manages files by both a unique logical formatdifferent from the MS-DOS compatible format, referred to below as thewrite-once format, and the MS-DOS compatible format. Similarly to theMS-DOS compatible format, the write-once format supervises the files inaccordance with the hierarchical directory structure.

[0121] The host equipment 2 of the present invention, which enables theuse of the memory card 1 according to the present invention (Ver2),records and/or reproduces data for the memory card 1 in accordance withthe write-once format. On the other hand, the conventional hostequipment, constructed with a view to employing the conventional memorycard (Ver1), records and/or reproduces data for the memory card 1 inaccordance with the MS-DOS compatible format. In the memory card 1according to the present invention, data is recorded by the hostequipment conforming to the memory card 1 (Ver2), while data managementis not performed in accordance with the MS-DOS compatible format. Inreading out data, recorded on the memory card 1 according to the presentinvention, by the host equipment conforming to the conventional memorycard (Ver1), session closure processing for recording the managementdata of the MS-DOS compatible format is performed. By performing thissession closure processing, readout compatibility with the conventionalequipment is achieved.

[0122] The memory card 1 according to the present invention is able toperform session closure processing a plural number of times. That is,even after the session closing processing is carried out once, filepost-write or update operations may be carried out in accordance withthe write-once format. Moreover, by carrying out the session closingoperation again, the file processed with post-write or update operationsmay be read out by the equipment conforming to the conventional memorycard (Ver1).

[0123] The write-once format applied to the present memory card 1 andthe session closing processing is hereinafter explained.

[0124] With the write-once format, the file entity data is recorded inthe block to which the logical address is pre-allocated, that is theeffective block. With the write-once format, the file entity data isrecorded on the block basis. That is, recording is made so that entitydata of plural files are not present together in one block. With thewrite-once format, recording of the file entity data is commenced fromthe leading page of the block. If, with the write-once format, entitydata of a file is recorded over plural blocks, the recording is made forblocks having consecutive logical addresses. The direction of theconsecutive logical addresses is the forward direction, that is thedirection continuously proceeding from a smaller number towards a largernumber. If a sub-directory entry in the MS-DOS compatible format, forexample, is recorded on the way such that entity data of a file cannotbe recorded in a sole area where there is a continuum of the logicaladdresses, the file entity data can be recorded in two partitions. Evenin such case, the respective areas in the two partitions are formed byblocks in each of which there persists a continuum of the logicaladdresses.

[0125] It is noted that, with the MS-DOS compatible format, the fileentity data can be recorded at random on the cluster basis. If theentity data is recorded in accordance with the above-describedwrite-once format rule, recording may be made at least on the cluster(block) basis. Consequently, the file entity data, recorded inaccordance with the write-once format, has also been recorded inaccordance with the MS-DOS compatible format.

[0126] With the write-once format, the file entity data is recorded inan area where there persists a continuum of logical addresses, so thataccessing may be made without the necessity of recording the informationindicating the cluster connecting sequence, such as FAT (File AllocationTable), as management data.

[0127] In the write-once format, the management data, termed an entrypage, is recorded in a block where the logical addresses are notpre-allocated (a block where the value of the logical address is not aninitial value (0×FFFF)), that is in a spare block. In the write-onceformat, one entry page is generated and recorded in the spare block eachtime a file is generated or updated or each time one root directory andone sub-directory are generated. The entry page has a capacity of onepage. Thus, one page of the spare block is consumed each time the file,root directory or the sub-directory is generated or updated.

[0128] In the write-once format, spare block management numbers are setfor all pages of the totality of the spare blocks. Since the number ofpages within one block is 32, the total number of pages for which thespare block management numbers are set is 992, 2046, 4064 and 8160 formemory cards of 16 Mbyte, 32 Mbyte, 64 Mbyte and 128 Mbyte,respectively.

[0129] Referring to FIG. 11, the spare block management numbers are setfrom the spare block of the physical block number of the lowermost order(that is, the spare block with the largest physical block number)towards the spare block of the physical block number of the uppermostorder, among the totality of the spare blocks. For the memory card 1 of128 Mbyte, for example, the spare block management numbers are set asshown in the following table. TABLE 1 spare block segment physical blockmanagement numbers numbers numbers page numbers  0 15 8191 0  1 15 81911  2 15 8191 2  3 15 8191 3 . . . . . . . . . . . . 31 15 8191 31  32 158190 0 33 15 8190 1 34 15 8190 2 . . . . . . . . . . . . 63 15 8190 31 64 15 8189 0 . . . . . . . . . . . . 511  15 7680 31  512  14 7679 0513  14 7679 1 . . . . . . . . . . . . 8158   0  494 30  8159   0  49431 

[0130] In the write-once format, the entry pages are recorded in thesequence conforming to the above spare block management numbers, eachtime one file etc. is generated or updated. That is, the entry pages arerecorded in the reverse direction to the usual recording direction ofthe entity data, that is, beginning from the rearmost spare block in thememory card 1.

[0131] The entry pages are now explained.

[0132] The entry pages are classified into five categories, that is, afile entry, a root entry, a sub-entry, a session anchor and a directorymarker.

[0133] The file entry is management data for specifying a file recordedon the memory card 1. When a file is recorded in the memory card 1, afile entry is recorded in the spare block in association with the sorecorded file. In the file entry are stated the name of the filespecified by the file entry, the attribute of the file, recordingposition information of the entity data of the file, the date ofgeneration of the file, a parent pointer and a fragment. The parentpointer is a spare block management number for a spare block where thereare recorded a root entry or a sub-entry specifying the parent directoryof the file. The fragment is the information indicating that the entitydata of a file is not recorded in a continuous region but is recorded ina fragmented condition. This fragment also indicates a start address fora recording area of a subsequent stage.

[0134] The root entry is management data specifying a root directory.The root directory is the uppermost directory in a hierarchicaldirectory structure. In file management by the hierarchical directorystructure, only one root directory is provided and remains unaltered. Itis therefore desirable that one such root directory is previouslyrecorded, at the time of plant shipment, in a leading page of the spareblock management number.

[0135] The sub-entry is the management data specifying a sub-directory.The sub-directory means any directory in the hierarchical directorystructure other than the root directory. The sub-directory may be placedbelow the root directory or below another sub-directory. If one suchsub-directory is generated in the memory card 1, one sub-directory isrecorded in the spare block in association with the so generatedsub-directory. In the sub-entry, there are stated the name of thesub-directory specified by the sub-entry, the date of generation of thesub-directory, and the information specifying the parent directory forthe sub-directory.

[0136] The session anchor is the management data indicating that sessionclosure processing has been performed. A pair of the session anchorsspecify that one session closing processing has been carried out. When asession closing processing is commenced, one session anchor is firstrecorded in a spare block and another session anchor is recorded in thespare block at the end of the session closure processing. In thissession anchor, there is recorded the information on the number of timesof the session closure processing performed on the memory card 1. Sincethe same value is recorded in the paired session anchors, the sessionanchor pair may be identified when reading out the file entry. Thesession anchor is recorded at the time of beginning and the end of thesession closure processing, in this manner, so that, when the powersupply is turned off during the session closure processing, such thatthe session closure has resulted in a failure, only one session anchoris recorded, thus allowing late recognition of the fact of failure ofthe session closing processing.

[0137] The directory marker indicates a recording position of thesub-directory entry which is the management data of the MS-DOScompatible format generated as a result of the session closingprocessing. This directory marker is recorded, in the session closingprocessing, after recording the first session anchor and beforerecording the second session anchor. That is, the directory marker isrecorded in a page sandwiched between the paired session anchors. Onesuch directory marker is recorded for one sub-directory entry newlyrecorded at the time of session closing. It should be noted that, if onesub-directory entry is recorded over plural blocks, a number of thedirectory markers corresponding to the number of the blocks is recordedfor one sub-directory entry.

[0138] The structure of the entry page is now explained in detail. Theentry page is recorded in a 152-byte data area in the page, as shown inFIG. 12.

[0139] A description field in the entry page is made up by a name field,a file attribute field, a species field, a leading block pointer field,a data size field, a generation date field, a parent pointer field, afragment field and a reserve field.

[0140] The name field is arrayed in 0'th to tenth bytes. If the entryfield is the file entry or the sub-entry, the name of the file specifiedby the entry page or the name of the sub-directory is recorded in thefield. When stating the name of the file and the sub-directory, it isstated with a letter string that is usable in the MS-DOS format.

[0141] It is noted that, if the filename is a long filename, prescribedby the MS-DOS compatible format, “0” is recorded in the leading one byteof the name field. The filename data length is stated in the nextfollowing two bytes, while the filename is recorded in the reservefield. If the entry page is the root entry or the directory marker, thename field is void.

[0142] If the entry page is the session anchor, a pair discriminationID, indicating the number of times of the session closing processingperformed on the memory card 1, is recorded in the 0'th to first byte ofthe name field. The pair discrimination ID is incremented in the orderof 1→2→3 . . . depending on the number of times of the session closingprocessing performed on the memory card 1. The maximum number of thenumber of times of the session closing processing is 8, such that thepair discrimination ID stated is only up to 8. Meanwhile, if the numberof times of the session closing processing is less than 8, and thepost-write capacity of the memory card 1 itself has become depleted, thepair discrimination ID is 256 (0×FFFF).

[0143] The attribute field is arrayed at the 11th byte. If the entrypage is the file entry, the attribute of the file specifying by the fileentry is stated in the attribute field. In the attribute field, “0”,“1”, “2”, and “3” are stated if the file attribute is the normal file,read-only file, a hidden file or a volume label, respectively. Theattribute file is void if the entry page is different than the fileentry.

[0144] The species field is arranged at the 12th byte. In this speciesfield, the species of the entry page is stated. That is, the informationas to whether the entry page is the file entry, root entry, sub-entry,session anchor or the directory marker is stated. If the entry page isthe file entry, root entry, sub-entry, session anchor or the directorymarker, “0”, “1”, “2”, “3” or “4” is stated, respectively, in thespecies field.

[0145] The leading block pointer field is arrayed at the 13th and 14thbytes. If the entry page is the file entry, the logical address of theleading block, where there is stored the file entity data, is stated inthe leading block pointer field. If the entry page is the rootdirectory, the logical address of the block, where the root directoryentry of the MS-DOS compatible format is stored, is stated in theleading block pointer field. If the entry page is the sub-entry or thesession anchor, the leading block pointer field is void. If the entrypage is the directory marker, the logical address of the block,specified by the directory marker, is stated in the leading blockpointer field.

[0146] The data size field is arrayed at the 15th to 18th bytes. If theentry page is the file entry, the size of the entity data of the filespecified by the file entry is stated on the byte order in the data sizefield. If the entry page is the directory marker, the first one ofentries recorded in the block specified by the directory marker isstated in the 0'th and the first byte of the data size field, whereas,in the second and third bytes thereof, the last one of entries stated inthe block is stated.

[0147] The date of generation field is arrayed in the 19th to 22ndbytes. In the date of generation field, the date of generation of thefile or the directory is stated, if the entry page is the file entry,root entry or the sub-entry. The statement of the date of generationfield is to be the same as that of the MS-DOS format. If the entry pageis the session anchor or the directory marker, the date of generationfield is void.

[0148] The parent pointer field is arrayed at the 23rd and 24th bytes.If the entry page is the file entry or the sub-entry, a parent pointeris stated in the parent pointer field. The parent pointer is the spareblock management number of the route entry or the sub-entry specifyingthe parent directory. If the entry page is the root entry, the parentblock management number of the own entry is stated in the parentpointer.

[0149] The fragment field is arrayed in the 25th to 28th bytes. In thefragment field, the information is recorded only when the entry page isthe file entry. The basis of the present write-once format is that thefile entity data is stored in the successive logical addresses. However,as an exceptional case, the data is fragmented into two chunks. In suchcase, that is when the file entity data is fragmented into two chunks, aflag indicating that effect is stated in the fragment field.Specifically, if the file entity data is fractionated, 0 (0×0000) isstated in the 0'th and first ones of the four bytes, whereas, if thefile entity data is not fractionated, data other than 0 is stated in the0'th and first bytes. If the file entity data is fractionated, thelogical address of the leading block where the latter portion of thefile entity data is recorded is stated in the second and third bytes.

[0150] The species-based image diagrams of the respective entry pagesare depicted in FIGS. 13A to 13F. Specifically, FIGS. 13A to 13F areimage diagrams of a file entry, a file entry (long file name), a rootentry, a sub-entry, a session anchor and a directory anchor,respectively.

[0151]FIG. 14 shows an example of a hierarchical directory structure ofthe files recorded in the memory card 1 and FIG. 15 shows an image ofthe entry page when the files of this hierarchical directory structureis recorded on the memory card 1. It is noted that arrows entered inFIG. 15 indicate the destination of the parent pointer stated in therespective file entries and sub-entries.

[0152] With the present write-once format, used in the memory card 1according to the present invention, it is possible to manage the filesby the hierarchical directory structure by recording the root entry,sub-entry and the file entry in association with the generated files anddirectories. That is, on booting the memory card 1, the host equipmentsequentially reads out all entry pages, beginning from the page with thespare block management number of zero. The totality of the entry pagesare read out to detect the values of the parent pointers stated in thefile entries and sub-entries. The parent-child relationship of the filesand the directories, recorded in the memory card 1, can be managed bydetecting the parent pointer in this manner.

[0153] In the file entry, there is stated the information on the storagelocations of the filenames and files. Consequently, the host equipmentis able to read out the file entity data by referencing these fileentries.

[0154] If, in the present write-once format, an arbitrary file is to beerased, the page status of the page, where there is recorded the fileentry specifying the file, is set to “0” to invalidate the page. Forexample, if the “file 6” is to be erased, as shown in FIG. 16, itsuffices to set “0” for the page status of the page where there isrecorded the “file entry 7” specifying the file 6 (page with the spareblock management number of “8”), as shown in FIG. 17. Thus, with thepresent write-once format, file erasure may also be made as the filesare supervised by the hierarchical directory structure, so that fileoperations may be carried out easily as in the case of accessing to theconventional memory card which may be rewritten a plural number oftimes.

[0155] Meanwhile, the erasure or movement of a sub-directory is possibleby regenerating and re-recording child files of the sub-directory andall entries pertinent to the child sub-directory. However, thisprocessing is extremely cumbersome. Thus, it is desirable not to changethe parent-child relationship on the way.

[0156] The session closing processing is hereinafter explained.

[0157] The file management data, other than entity data, in the MS-DOScompatible format, may be exemplified by MBR (master boot record), PBR(partition boot record), FAT (file allocation table), root directoryentry and the sub-directory entry.

[0158] The MBR is the information arrayed at the leading end of a userarea and states the boot information to the respective partitions. Inthe memory card 1 of the present invention, there is only one partition.The PBR is the information arrayed in the leading sector of thepartition and states various information pertinent to the respectivepartitions. The FAT records the connecting state of the clusters(blocks) handled in the user area. The present memory card 1 records twoFATs (FAT1, FAT2) by way of backup. The root directory entry states theentries of respective files and sub-directories arranged in the rootdirectory. The sub-directory entry states the entries of respectivefiles and sub-directories arranged in the sub-directory. Each directoryis composed of two bytes in which there are stated the filename,attributes, recording date, beginning cluster (block) number and thefile size (in byte unit).

[0159] The MS-DOS compatible format prescribes that these managementdata shall be recorded in the clusters having the logical addressesallocated thereto. In the memory card 1 of the present invention, thecluster is a block. The session closing processing is such processing inwhich the aforementioned management data of the MS-DOS compatible formatare post-recorded to the blocks, having the logical addresses allocatedthereto, by having reference to the contents of the management datarecorded in accordance with the write-once format, to provide forreadout compatibility with respect to the equipment adapted for copingwith the conventional memory card. Although the logical addresses of thePBR are stated in the MBR, these need not be re-written insofar as thelogical addresses of the PBR are not changed. Conversely, the PBR, FAT,root directory and the sub-directory entry need to be rewrittenresponsive to the post-writing of the structure of files or directories.Thus, in the session closing processing, the PBR, FAT, root directoryand the sub-directory entry are generated and recorded, even though theMBR is not generated nor recorded.

[0160] The process steps of the session closing processing are nowexplained by referring to the flowchart shown in FIG. 18.

[0161] First, in a step S1, the host equipment 2 writes the firstsession anchor in the spare block management number next following thelast recorded entry page. At this time, the host equipment 2 states thepair discrimination ID in the name field of the first session anchor. Inthis pair discrimination ID, a number indicating the number of times ofthe session closing processing performed on the present memory card 1 isstated. For example, “1” and “2” are stated for the first sessionclosing processing and for the second session closing processing,respectively.

[0162] In the next step S2, the host equipment generates the PBR and theFAT, corresponding to the file management state at the current timepoint, based on the management data of the write-once format, andrecords the generated PBR and FAT on the memory card 1.

[0163] The FAT states the connection sequence of the blocks (clusters).This connection sequence may be generated by analyzing the file entry,root entry, sub-entry and the directory marker in the write-once format.It is because the write-once format prescribes that entity data forminga file basically shall be recorded in a block bearing a continuum oflogical addresses, and that, if the entity data is partitioned into twochunks, the logical addresses of the latter chunk shall be stated by thefragment of the file entry.

[0164] It is noted that, in the first session closing processing, thehost equipment records the PBR and the FAT in the effective block wherethe logical addresses are allocated as the outset. The block where thePBR and the FAT are recorded is stated in the MBR. This block is, forexample, a block with the logical address of 1 or 2, that is, the hostequipment records the PBR and the FAT for the block of the logicaladdress indicated in the MBR.

[0165] In the second and following session closing processing, the hostequipment records the PBR and the FAT in the spare block where thelogical address has not been recorded. In this spare block, the PBR andthe FAT are recorded in the 0 segment spare block. That is, the PBR andthe FAT are recorded such that the reserve area is consumed from aregion opposite to the management data (entry page) of the write-onceformat. The host equipment 2 sets the block use status of the recordedblock to “0”, while also recording the logical address. The value of thelogical address is the same as that of logical address of the blockwhere the original PBR and FAT have been recorded at the time of theprevious session closing processing. The host equipment 2 then sets to“0” the block status of the block where the original PBR and FAT havebeen recorded at the time of the previous session closing processing.Finally, the host equipment 2 updates the conversion table of thelogical address-physical block number the host equipment internallyholds.

[0166] At the next step S3, the host equipment 2 generates a rootdirectory entry and a sub-directory, which are in keeping with thecurrent file management condition, based on the management data of thewrite-once format, and records the so generated root directory entry andthe sub-directory.

[0167] It is noted that, at the time of the first session closingprocessing, the host equipment 2 records the root directory and thesub-directory entry in the effective block which is a block where thelogical address has been pre-allocated. The block where the rootdirectory is recorded is stated in the PBR. Thus, the host equipment 2records the root directory entry in the block of the logical addressindicated in this PBR. The host equipment 2 records the sub-directoryentry in the effective blocks as from the segment 1.

[0168] In the second and the following session closing processing, thehost equipment 2 records the root directory entry and the sub-directoryentry in the spare block which is a block where no logical address hasbeen pre-allocated. The host equipment 2 records the root directoryentry in the segment 0 spare block among the spare blocks. That is, thehost equipment records the root directory entry so that the reserve areawill be consumed from an area opposite to the management data of thewrite-once format. The host equipment 2 records the sub-directory entryin the spare blocks as from the segment 1. However, even in the secondand the following session closing processing, the sub-directory entry ofthe sub-directory generated for the first time, that is thesub-directory newly generated as from the previous session closingprocessing, is recorded in the effective block which is the block wherethe logical address has been preallocated. Even in this case, thesub-directory entry is recorded in the effective blocks as from thesegment 1. If the root directory entry or the sub-directory entry hasbeen recorded in the spare block, the host equipment 2 sets the blockuse state of the block to “0”, while recording the logical address. Thevalue of the logical address recorded is to be the same as that of thelogical address of the block where the root directory entry or thesub-directory entry recorded at the time of previous session closingprocessing has been recorded. If the root directory entry or thesub-directory entry is recorded in the spare block, the host equipment 2sets “0” for the block status of the block, where the root directoryentry or the sub-directory entry recorded at the time of previoussession closing processing has been recorded. Finally, the hostequipment 2 updates the conversion table of the logical address-physicalblock number the host equipment internally holds.

[0169] If the host equipment 2 has added or updated the sub-directoryentry, the host equipment 2 in a step S4 writes the directory marker forthe so added or updated sub-directory entry in the spare block next tothe session anchor recorded in the step S1.

[0170] Meanwhile, in the MS-DOS compatible format, each entry formingthe root directory or the sub-directory is of a data size of 4 bytes (32bits). Since the MS-DOS compatible format provides that the number ofthe files or the sub-directories below the root directory, that is, thenumber of entries, shall be up to 512, the capacity of the entity dataof the root directory entries is one block (512 bytes×32 pages) at themaximum. That is, the root directory entries are necessarily comprisedin one block. Conversely, there is no provision in the MS-DOS compatibleformat as to the number of the files and sub-directories below thesub-directory. Thus, the capacity of the entity data of thesub-directory entries occasionally exceeds one block. In such case, thesub-directory entries are recorded over plural blocks.

[0171] When the sub-directory entries are recorded over plural blocks,the host equipment 2 also records plural directory markers in onesub-directory. In more detail, if the number of the entries in thesub-directory is up to 512 (one block), the logical address of the blockwhere the entity data of the sub-directory entry are recorded is statedby one directory marker. When the number of the entries in thesub-directory exceeds 512, a directory marker is created from block toblock for the excess entries to indicate the range of the entriesindicated in the block by way of discrimination.

[0172] When the sub-directory has been updated, there persists thedirectory marker recorded at the time of the directly previous andfurther previous session closing processing. In such case, the pagestatus of the page containing the directory marker recorded at the timeof the directly previous and further previous session closing processingis set to “0” for erasure.

[0173] In the next step S5, the host equipment 2 records the secondsession anchor next to the directory marker if such directory marker wasrecorded in the step S4 and next to the first session anchor, recordedin the step S1, if the directory marker was not recorded in the step S4.At this time, the host equipment states the same pair discrimination IDas that recorded in the first session anchor in the second sessionanchor.

[0174] By the above-described session closing processing, the hostequipment is able to convert the memory card 1, supervised by thewrite-once format, into that supervised by the MS-DOS compatible format.

[0175] An exemplary hierarchical directory structure of the filesrecorded in the memory card 1 of the present invention, as well as therecording image of the entry pages and the recording image of the datarecording region when the files of the hierarchical directory structurehave been recorded in the memory card 1 , are shown, by way ofexplanation of a specified instance of the session closing processing.

[0176] The memory card 1 of the present invention is supplied to theuser after the first session closing processing carried out at the timeof shipment from the plant. For example, prior to the first sessionclosing processing (prior to shipment from the plant), the rootdirectory and a “MEMSTICK. ind.” file are recorded on the memory card 1,as shown in FIG. 19. It is now assumed that the first session closureprocessing is carried out after recording these files. Meanwhile, the“MEMSTICK. ind.” file is a file stating the information indicating thatthe present device is the write-once memory card, and is generated belowthe root directory. In this recording state, the memory card 1 executesthe first session closing processing.

[0177]FIG. 20 shows a recording image of the management data of thewrite-once format following the first session closing processing. Priorto the first session closing processing, the root entry and the fieentry (MEM) indicating the “MEMSTICK. ind.” file have been recorded in apage area of the spare block management numbers of 0 and 1 in the memorycard 1. After the end of the session closing processing, two sessionanchors (with the pair discrimination ID being “1”) are recorded in apage area of the spare block management numbers of 2 to 3 in the memorycard 1.

[0178]FIG. 21 shows a recording image of the management data and theentity data following the first session closing processing. As shown inFIG. 21, boot is recorded in the blocks with the physical addresses of“0” to “1”. The MBR is recorded in the block with the logical address of“0” (physical block number of 2), while the PBR and the FAT are recordedin the blocks with the logical addresses of “1” to “2” (physical blocknumbers of 3 to 4). The root directory entry is recorded in the blockswith the logical address of “3” (physical block number of 5), while theentity data of the “MEMSTICK. ind.” file are recorded in the blocks withthe logical address of “4”.

[0179] It is assumed that a file shown for example in FIG. 22 isrecorded in the memory card 1 following the first session closingprocessing described above, that is that the first file (File1), secondfile (File2) and the first sub-directory (Sub1) are post-written belowthe root directory, that the third file (File3) is post-written belowthe first sub-directory (Sub1) and that the second session closingprocessing is subsequently performed.

[0180]FIG. 23 shows a recording image of management data of thewrite-once format following the second session closing processing. FIG.24 shows a recording image of the management data and the entity data ofthe MS-DOS compatible format following the second session closingprocessing.

[0181] Following the first session closing processing and before secondsession closing processing, a file entry (1), specifying the first file(File1), a file entry (2), specifying the second file (File2), asub-entry (1), specifying the first sub-directory (Sub1) and a fileentry (3), specifying a third file (File3), are recorded in the pagearea of the spare block management numbers 4 to 7 of the memory card 1.The entity data of the first file (File1), the second file (File2) andthe third file (File3) are recorded in the segment 0 data recordingarea.

[0182] If, in the above state, the second session closing processing iscarried out, a first session anchor (with the pair discrimination ID of“2”), the directory mark (1) specifying the block where thesub-directory entry as the entity of the first sub-directory (Sub1) isstored, and the second session anchor (with the pair discrimination IDof “2”) are recorded in the page area of the spare block managementnumbers of 8 to 10.

[0183] The root directory, FAT and PBR updated are recorded in theleading spare block (with the physical numbers of 494 to 496) in thesegment 0. In the respective blocks, where the root directory, FAT andPBR are recorded, there is recorded the same logical address as thelogical address of the block where the original root directory, FAT andPBR prior to updating were recorded. Specifically, the logical addresses1 to 3 are recorded in the blocks of the physical block numbers of 494to 496. By the second session closing processing, a sub-directoryentry(1) of the first sub-directory (Sub1) is newly formulated andrecorded in the recording area (block with the physical block number of512 and the logical address of 492) of the segment 1. The PBR, FAT andthe root directory, recorded at the time of the first session closingprocessing, are then erased. That is, the block status of the blockswith the physical block numbers of 3, 4 and 5 is set to “0”.

[0184] It is assumed that files shown for example in FIG. 25 are addedto the memory card 1 following the second session closing processingdescribed above. That is, it is assumed that a fourth file (File4), asecond sub-directory (Sub2), a fifth file (File5) and a sixth file(File6) are post-written below the root directory, first sub-directory(Sub1), second sub-directory (Sub2) and below the first sub-directory(Sub1), respectively. It is moreover assumed that a third sessionclosing processing is subsequently carried out.

[0185]FIG. 26 shows a recording image of the management data of thewrite-once format following the third session closing processing. FIG.27 shows a recording image of the management data and the entity data ofthe MS-DOS compatible format following the third session closingprocessing.

[0186] Following the second session closing processing and before thethird session closing processing, a file entry (4), specifying thefourth file (File4), a sub-entry (2), specifying a second sub-directory(Sub2), a file entry (5), specifying a fifth file (File6) and a fileentry (6), specifying a sixth file (File6) are recorded in page areas ofthe memory card 1 having the spare block management numbers of 11 to 14,respectively. The entity data of the fourth file (File4) and the fifthfile (File5) are recorded in the data recording area of the segment 0.The entity data of the sixth file (File6) is fragmented in two chunkswhich are recorded in the data area of the segment 0 and the data areaof the segment 1. The first sub-directory entry (1) is inserted on theway in the entity data of the sixth file such that the logical addressesof the two areas fragmented are not consecutive to each other. In suchcase, a fragment is recorded in the file entry (6).

[0187] If, in the above state, the third session closing processing isexecuted, the first session anchor, with the pair discrimination ID of“3”, a directory mark (2) specifying the block where there is stored thesub-directory entry as the entity of the first sub-directory (Sub2), andthe second session anchor, with the pair discrimination ID of “3”, arerecorded in page areas with the spare block management numbers of 15 to17, respectively.

[0188] The root directory, FAT and PBR updated are recorded in the spareblock (with the physical numbers of 497 to 499) in the segment 0. In therespective blocks, where the root directory, FAT and PBR are recorded,there are recorded the same logical addresses as the logical addressesof the blocks where the original root directory, FAT and PBR prior toupdating were recorded. Specifically, the logical addresses 1 to 3 arerecorded in the block of the physical block numbers of 497 to 499. Thesub-directory entry (1) of the updated first sub-directory (1) isrecorded in the leading spare block (with the physical block number of1006) in the segment 1. In the block where the sub-directory entry (1)is recorded, there is recorded the same logical address as the logicaladdress of the block where the original root directory entry (1) priorto updating was recorded. Specifically, the logical address 494 isrecorded in the block of the physical block number of 1004.

[0189] By the third session closing processing, the sub-directory entry(1) of the second sub-directory (Sub1) is newly formulated and recordedin the leading end of the vacant block of the data recording area of thesegment 1 (for example, the block with the physical block number of 613and the logical address of 593). The PBR, FAT and the root directoryrecorded during the second session closing processing and thesub-directory entry (1) of the first sub-directory (1) are then erased.That is, the block statuses of the blocks with the physical blocknumbers of 494, 495 and 496 and the block with the physical block numberof 510 are set to “0”.

[0190] The present invention is not limited to the embodiments describedwith reference to the drawings and, as may be apparent to those skilledin the art, various changes, substitutions or equivalents may beenvisaged without departing from the scope and the purport of theinvention as defined in the appended claims.

Industrial Applicability

[0191] According to the present invention, described above, a datarecording area of a recording medium, in which data can be written onlyonce on the bit basis, is divided into an entity data recording area forrecording entity data of a file and a management data recording area forrecording management data for supervising the recorded files by ahierarchical directory structure. In the management data recording area,a file entry for specifying a file recorded on the recording medium, aroot entry for specifying the uppermost order directory in thehierarchical directory structure and a sub-entry for specifying asub-directory in the hierarchical directory structure, are recorded inassociation with the file, root directory and the sub-directorygenerated, respectively. In the file entry are included the name of thefile specified, the information identifying the root entry or thesub-entry specifying the parent directory of the file and theinformation for identifying a recorded position of the entity data ofthe file. In the sub-entry are included the name of the sub-directoryspecified and the information identifying the root entry or thesub-entry specifying the parent directory of the subdirectory.

[0192] By supervising the recording medium, capable of writing data onlyonce on the bit basis, as described above, it is possible with thepresent invention to manage the files, recorded on the write-oncememory, in accordance with the hierarchical directory structure.

[0193] According to the present invention, the data recording area of arecording medium, capable of writing data only once on the bit basis, isdivided into an entity data recording area for recording the entity dataof the file(s), and a management data recording area for recordingmanagement data supervising the recorded files by the hierarchicaldirectory structure, and the so divided data recording area issupervised. In the management data recording area, a file entry forspecifying a file recorded on a recording medium, a root entry forspecifying the uppermost order directory in the hierarchical directorystructure and a sub-entry for specifying a sub-directory in thehierarchical directory structure, are recorded in association with thefile, root directory and the sub-directory generated, respectively. Inthe file entry are included the name of the file specified, theinformation identifying the root entry or the sub-entry specifying theparent directory of the file and the information for identifying therecorded position of the entity data of the file. In the sub-entry areincluded the name of the sub-directory specified and the informationidentifying the root entry or the sub-entry specifying the parentdirectory of the sub-directory.

[0194] Moreover, according to the present invention, the physical formatof the entity data recording area is identified with the physical formatof the effective area in a rewritable memory device having a memorydevice in which data can be rewritten a plural number of times and whichincludes an effective area set for recording entity data and a reservearea set for data substitution, while the physical format of themanagement information recording area is identified with the physicalformat of the reserve area in the rewritable memory device.

[0195] By supervising the recording medium in which data can berewritten only once on the bit basis, it is possible to provide forcompatibility with the memory device employing a memory on which datacan be written a plural number of times.

1. A memory device having a recording medium on which data can bewritten only once on the bit basis and which includes an entity datarecording area for recording entity data of a file and a management datarecording area for recording management data supervising the recordedfiles by a hierarchical directory structure; wherein in said managementdata recording area, a file entry for specifying a file recorded on therecording medium, a root entry for specifying the uppermost orderdirectory in the hierarchical directory structure and a sub-entry forspecifying a sub-directory in the hierarchical directory structure, arerecorded as said management data in association with the file(s), rootdirectory and the sub-directory generated, respectively; the name of thefile specified, the information identifying the root entry or thesub-entry specifying the parent directory of the file, and theinformation for identifying a recording position of the entity data ofthe file, are included in said file entry; and wherein the name of thesub-directory specified and the information identifying the root entryor the sub-entry specifying the parent directory of said sub-directoryare included in said sub-entry.
 2. The memory device according to claim1 wherein said entity data recording area and the management datarecording area are each divided into blocks, each of which represents apredetermined data unit; a logical address is recorded in each block ofsaid entity data recording area; only entity data of a file is recordedin one block of said entity data recording area; and wherein entity dataof one file is recorded in one or more blocks formed by consecutivelogical addresses.
 3. The memory device according to claim 2 whereinsaid block is formed by a plurality of pages each being of apredetermined data volume.
 4. The memory device according to claim 3wherein an intra-page data recording area for recording entity data ormanagement data, and an additional data recording area for recordingadditional data, are provided in said page, and wherein an area forrecording the logical address of a block containing the page is providedin said additional data recording area.
 5. The memory device accordingto claim 4 wherein an area for recording a logical address ispre-recorded in each block of said entity data recording area prior tothe recording of the entity data.
 6. The memory device according toclaim 5 wherein said logical address is recorded at least in a leadingpage of each block.
 7. The memory device according to claim 3 whereinone root entry, a sub-entry and a file entry are recorded on one page; amanagement address is set in each page of said management data recordingarea; and wherein a management address for a root entry or a sub-entryspecifying a parent directory is included in said sub-entry and in saidfile entry as being the information specifying said root entry or thesub-entry of the parent directory.
 8. The memory device according toclaim 2 wherein an area for recording a data use status flag indicatingthe fact of the recording of the entity data is provided in each blockof said entity data recording area.
 9. The memory device according toclaim 2 wherein an area for recording a page status flag indicating thefact of deletion of a sub-directory or a file specified by a sub-entryor a file entry recorded in said page is provided in the additional datarecording area in each page of said management data recording area. 10.The memory device according to claim 1 wherein said recording medium isa write-once non-volatile memory.
 11. A file management method for arecording medium on which data can be written only once on the bitbasis, comprising: dividing a data recording area on said recordingmedium into an entity data recording area for recording entity data of afile and a management data recording area for recording management datasupervising the recorded files by a hierarchical directory structure,and supervising the so divided data recording area; recording a fileentry, specifying a file recorded on a recording medium, a root entryfor specifying the uppermost order directory in the hierarchicaldirectory structure and a sub-entry for specifying a sub-directory inthe hierarchical directory structure, in the management data recordingarea, in association with the file, root directory and the sub-directorygenerated, respectively; including the name of the file specified, theinformation identifying the root entry or the sub-entry specifying aparent directory of the file and the information for identifying arecorded position of the entity data of the file in said file entry; andincluding the name of the sub-directory specified and the informationidentifying the root entry or the sub-entry specifying a parentdirectory of the sub-directory in said sub-entry.
 12. The filemanagement method according to claim 11 further comprising: referencingsaid file entry, root entry and the sub-entry, recorded in saidmanagement data recording area, and supervising the hierarchicaldirectory structure of the recorded files, based on the names indicatedin these entries and the information identifying the root entry or thesub-entry specifying the parent directory; and referencing said fileentry, root entry and the sub-entry, recorded in said management datarecording area, and reading out entity data of a predetermined file fromthe entity data recording area based on the information identifying therecording position of the entity data of the file indicated in theseentries.
 13. The file management method according to claim 12 furthercomprising: dividing said entity data recording area and the managementdata recording area into blocks as predetermined data units andsupervising the so divided recording areas; recording a logical addressin each of blocks of said entity data recording area; recording onlyentity data of one file in one block of said entity data recording area;and recording the entity data of one file in one or more blocks formedby consecutive logical addresses.
 14. The file management methodaccording to claim 13 further comprising: forming said block from aplurality of pages each of a predetermined data volume and supervisingthe so divided block.
 15. The file management method according to claim14 further comprising: dividing said page into an intra-page datarecording area for recording entity data or management data and anadditional data recording area for recording additional data, andsupervising the so divided page; and recording the logical address of ablock containing said page in said additional data recording area. 16.The file management method according to claim 15 further comprising:pre-recording a logical address in each block of said entity datarecording area prior to the recording of the entity data.
 17. The filemanagement method according to claim 16 wherein said logical address isrecorded in a leading page in each block.
 18. The file management methodaccording to claim 14 further comprising: recording one root entry, asub-entry and a file entry on one page; setting a management address foreach page of said management data recording area; and including amanagement address of the root entry or the sub-entry specifying theparent directory in said sub-entry and said file entry as theinformation identifying the root entry or the sub-entry of the parentdirectory.
 19. The file management method according to claim 14 wherein,if entity data is recorded in said entity data recording area, a datause status flag, indicating the fact of recording the entity data isrecorded, for a block having the entity data recorded therein.
 20. Thefile management method according to claim 14 wherein, if a file or asub-directory being supervised is deleted, a page status flag,indicating the fact of deletion of the sub-directory or the file,specified by the sub-entry or the file entry recorded in said page, inthe additional data recording area in each page of the management datarecording area.
 21. The file management method according to claim 11wherein said recording medium is a write-once non-volatile memory.
 22. Arecording and/or reproducing apparatus having a recording and/orreproducing unit for recording and/or reproducing a file for a memorydevice including a recording medium on which data can be written onlyonce on the bit basis and which is provided with an entity datarecording area for recording entity data of said files and a managementdata recording area for recording management data supervising therecorded files in accordance with a hierarchical directory structure;said recording and/or reproducing unit in recording data recording theentity data of said files in said entity data recording area; recordinga file entry, specifying the files recorded on a recording medium, aroot entry for specifying the uppermost order directory in thehierarchical directory structure and a sub-entry for specifying asub-directory in the hierarchical directory structure, in saidmanagement data recording area, in association with the file, rootdirectory and the sub-directory generated, respectively; including thename of the file specified, the information identifying the root entryor the sub-entry specifying a parent directory of said file and theinformation for identifying a recorded position of the entity data ofsaid file, in said file entry; and including the name of thesub-directory specified and the information identifying the root entryor the sub-entry specifying the parent directory of the sub-directory,in said sub-entry; said recording and/or reproducing unit in reproducingdata referencing said file entry, root entry and the sub-entry, recordedin said management data recording area, and supervising the hierarchicaldirectory structure of the recorded files, based on the names indicatedin these entries and the information identifying the root entry or thesub-entry specifying the parent directory; and referencing said fileentry, root entry and the sub-entry, recorded in said management datarecording area, and reading out entity data of a predetermined file fromthe entity data recording area based on the information identifying therecording position of the entity data of the file indicated in theseentries.
 23. The recording and/or reproducing apparatus according toclaim 22 wherein said entity data recording area and the management datarecording area are divided into blocks each being a predetermined dataunit; a logical address is recorded in each block of said entity datarecording area; said recording and/or reproducing unit recording entitydata of a file in one or more blocks formed by consecutive logicaladdresses; only entity data of one file is recorded in one block of saidentity data recording area; and wherein said file entry includes, as theinformation identifying the recording position of the entity data, thelogical address of the leading block of the entity data of a file and adata length of the entity data.
 24. The recording and/or reproducingapparatus according to claim 23 wherein said block is made up by aplurality of pages each being of a predetermined data volume.
 25. Therecording and/or reproducing apparatus according to claim 24 wherein amanagement address is set for each page of said management datarecording area; and wherein said recording and/or reproducing unitrecords one route entry, a sub-entry and a file entry in one page; saidsub-entry and file entry including a management address of a route entryor a sub-entry specifying a parent directory as being the informationidentifying the route entry or the sub-entry of the parent directory.26. The recording and/or reproducing apparatus according to claim 24wherein if entity data has been recorded in said entity data recordingarea, said recording and/or reproducing unit records a data use statusflag indicating the fact of the recording of the entity data, in a blockwhere entity data has been recorded.
 27. The recording and/orreproducing apparatus according to claim 24 wherein if said file or thesub-directory is to be deleted, said recording and/or reproducing unitrecords a page status flag, indicating the fact of deletion of the fileor the sub-entry specified by a file or a sub-entry recorded in saidpage.
 28. The recording and/or reproducing apparatus according to claim22 wherein said recording medium is a write-once non-volatilesemiconductor memory.
 29. A write-once memory device having a recordingmedium on which data can be written only once on the bit basis and whichincludes an entity data recording area where entity data of a file isrecorded and a management data recording area where management data forthe write-once format for supervising said files in accordance with ahierarchical directory structure is recorded, wherein a file entry,specifying a file recorded on a recording medium, a root entry forspecifying the uppermost order directory in the hierarchical directorystructure and a sub-entry for specifying a sub-directory in thehierarchical directory structure, are recorded in the management datarecording area, in association with the file, root directory and thesub-directory generated, respectively; the name of the file specified,the information identifying the root entry or the sub-entry specifying aparent directory of said file and the information for identifying arecorded position of the entity data of said file(s) are included in thefile entry; the name of the sub-directory specified and the informationidentifying the root entry or the sub-entry specifying a parentdirectory of the sub-directory are included in the sub-entry; thephysical format of said entity data recording area is identified withthe physical format of an effective area of a recording medium of arewritable memory device capable of re-writing data a plural number oftimes and having the effective area and a reserve area for datasubstitution, said effective area being an area where entity data isrecorded; and wherein the physical format of said management datarecording area is identified with the physical format of said reservearea in said rewritable memory device.
 30. The write-once memory deviceaccording to claim 29 wherein said entity data recording area and themanagement data recording area are each divided into blocks each being apredetermined data unit which is the same as the data unit of thephysical format of the effective area and the reserve area of saidrewritable memory device.
 31. The write-once memory device according toclaim 30 wherein a file allocation table, a root directory and asub-directory of the same format as that of the file management data ofsaid rewritable recording medium are recorded in said entity datarecording area or the management data recording area; said fileallocation table states a connection sequence of said blocks; said rootdirectory states an entry which is the information stating the names ofthe files and the sub-directories arranged in the uppermost orderdirectory in the hierarchical directory structure and the recordingpositions of entity data of the sub-directories; and wherein saidsub-directories state the entries for the files in the sub-directoriesand the sub-directories.
 32. The write-once memory device according toclaim 31 wherein the physical format of the effective area and thereserve area of said rewritable memory device is divided into blockseach being a predetermined data unit, each block having a physical blocknumber set therefor; and wherein the entity data recording area and themanagement data recording area are divided into blocks, which are thesame as those of the rewritable memory device, and in each of which thesame physical block number as that of the rewritable memory device isset.
 33. The write-once memory device according to claim 32 wherein thephysical address is recorded in each block of the entity data recordingarea.
 34. The write-once memory device according to claim 33 whereinonly entity data of one file are recorded in one block of said entitydata recording area and wherein entity data of one file is recorded inone or more blocks formed by consecutive logical addresses.
 35. Thewrite-once memory device according to claim 34 wherein said block isformed by a plurality of pages each being of a predetermined datavolume.
 36. The write-once memory device according to claim 35 whereinone root entry, a sub-entry and a file entry are recorded on one page; amanagement address is set for each page of said management datarecording area; and wherein said management address is included in saidsub-entry and said file entry as the information identifying the rootentry or the sub-entry of the parent directory.
 37. The write-oncememory device according to claim 36 wherein the root entry, sub-entryand the file entry are consecutively recorded from one of the lowerorder side and the upper order side of the management addresses.
 38. Thewrite-once memory device according to claim 37 wherein the fileallocation table, root directory and the sub-directory, initiallyrecorded on a recording medium, are recorded in said entity datarecording area, and wherein the file allocation table, root directoryand the sub-directory, recorded updated, are recorded in the managementdata recording area.
 39. The write-once memory device according to claim38 wherein the file allocation table, root directory and thesub-directory, initially recorded on a recording medium, recordedupdated, are consecutively recorded from one of the upper order side andthe lower order side of the management addresses opposite to the sidefrom which the management data for the write-once format is recorded.40. The write-once memory device according to claim 39 wherein thelogical address of the block where the file allocation table, rootdirectory and the sub-directory yet to be updated are recorded isrecorded in a block of a management data recording area where said fileallocation table, root directory and the sub-directory are recordedupdated.
 41. The write-once memory device according to claim 40 whereinan area for recording a block status flag indicating the fact ofdeletion of the entity data recorded in the block is provided in eachblock of the entity data recording area and the management datarecording area.
 42. The write-once memory device according to claim 41wherein a session anchor indicating the fact of updating is recorded inthe management data recording area next to the management data for thewrite-once format.
 43. The write-once memory device according to claim42 wherein at least two pages of the session anchor are recorded. 44.The write-once memory device according to claim 29 wherein saidrecording medium is a write-once non-volatile semiconductor memory. 45.A file management method for a write-once recording medium on which datacan be written only once on the bit basis, comprising: dividing arecording area of said write-once recording medium into an entity datarecording area for recording entity data of files and a management datarecording area for recording management data for the write-once formatsupervising the recorded files in accordance with a hierarchicaldirectory structure, and supervising the so divided data recording area;recording a file entry, specifying a file recorded on said recordingmedium, a root entry for specifying the uppermost order directory in thehierarchical directory structure and a sub-entry for specifying asub-directory in the hierarchical directory structure, as managementdata for the write-once format, in the management data recording area,in association with the file, root directory and the sub-directorygenerated; including the name of the file specified, the informationidentifying the root entry or the sub-entry specifying a parentdirectory of said file and the information for identifying a recordedposition of the entity data of the file, in said file entry; andincluding the name of the sub-directory specified and the informationidentifying the root entry or the sub-entry specifying the parentdirectory of the sub-directory, in said sub-entry; supervising saidentity data recording area as being of the same physical format as thephysical format of an effective area of a rewritable recording mediumcapable of rewriting data a plural number of times, said effective areabeing an area where entity data are recorded, said rewritable recordingmedium having a reserve area for data substitution in addition to saideffective area; and supervising said management data recording area asbeing of the same physical format as that of said reserve area in saidrewritable recording medium.
 46. The file management method according toclaim 45 wherein said entity data recording area and the management datarecording area are divided into blocks each being of the samepredetermined data unit as that of the physical format of said effectivearea and the reserve area of said rewritable recording medium.
 47. Thefile management method according to claim 46 wherein a file allocationtable, a root directory and a sub-directory of the same format as thatof the file management data of said rewritable recording medium arerecorded in said entity data recording area or the management datarecording area; the connection sequence of said blocks is stated in saidfile allocation table; an entry which is the information stating thenames of the files and sub-directories arranged in an uppermost orderdirectory in the hierarchical directory structure and the recordingpositions of the entity data of the respective files and thesub-directories is stated in said root directory; and wherein theentries of the files and the sub-directories arranged in thesub-directories are stated in the sub-directories.
 48. The filemanagement method according to claim 46 wherein a hierarchical directorystructure of files identified by management data for the write-onceformat recorded in the management data recording area and the rootdirectory as well as the sub-directories supervising the files by thesame hierarchical directory structure are recorded in the entity datarecording area or in the management data recording area; and wherein afile allocation table stating the connection sequence of the blocksidentified by the management data for the write-once format recorded inthe management data recording area is also recorded in the entity datarecording area or in the management data recording area.
 49. The filemanagement method according to claim 48 wherein a logical address isrecorded in each block of said entity data recording area to superviseeach block.
 50. The file management method according to claim 49 whereinentity data of only one file is recorded in one block of said entitydata recording area and wherein entity data of one file is recorded inone or more blocks formed by consecutive logical addresses.
 51. The filemanagement method according to claim 50 wherein said block is formed byand supervised as a plurality of pages each being of a predetermineddata volume.
 52. The file management method according to claim 51wherein one root entry, a sub-entry and a file entry are recorded on onepage, a management address is set for each page of said management datarecording area, and wherein said management address is included in saidsub-entry and said file entry as the information identifying the rootentry or the sub-entry of the parent directory.
 53. The file managementmethod according to claim 51 wherein the root entry, sub-entry and thefile entry are consecutively recorded from one of the lower order sideand the upper order side of the management addresses.
 54. The filemanagement method according to claim 53 wherein the file allocationtable, root directory and the sub-directory, initially recorded on awrite-once recording medium, are recorded in said entity data recordingarea, and wherein the file allocation table, root directory and thesub-directory, recorded updated, are recorded in the management datarecording area.
 55. The file management method according to claim 54wherein the file allocation table, root directory and the sub-directory,recorded updated, are consecutively recorded from one of the upper orderside and the lower order side of the management addresses opposite tothe side from which the management data for the write-once format isrecorded.
 56. The file management method according to claim 55 whereinthe logical address of the block where the file allocation table, rootdirectory and the sub-directory yet to be updated are recorded isrecorded in a block where said file allocation table, root directory andthe sub-directory are recorded updated.
 57. The file management methodaccording to claim 56 wherein a block status flag indicating the fact ofdeletion of the entity data recorded in a block where the fileallocation table, root directory and the sub-directory yet to be updatedare recorded, is recorded in said block.
 58. The file management methodaccording to claim 57 wherein, when a file is updated, a session anchorindicating the fact of updating the file is recorded in the managementdata recording area next to the management data for the write-onceformat.
 59. The file management method according to claim 58 wherein atleast two pages of the session anchor are recorded.
 60. The filemanagement method according to claim 45 wherein said recording medium isa write-once non-volatile semiconductor memory.
 61. A recording and/orreproducing apparatus having a recording and/or reproducing unit forrecording and/or reproducing a file recorded on a one-time memory deviceincluding a recording medium capable of re-writing data on the bitbasis, said recording medium having an entity data recording area forrecording entity data of the file(s) and a recording area for managementdata for a write-once format for recording management data supervisingthe files in accordance with a hierarchical directory structure; saidrecording and/or reproducing unit recording a file entry for specifyinga file recorded on said recording medium, a root entry specifying anuppermost order directory in the hierarchical directory structure and asub-entry specifying a sub-directory in the hierarchical directorystructure, as said management data for the write-once format, inassociation with the file, root directory and the sub-directorygenerated, respectively, in said management data recording area;including the name of the file specified, the information identifyingthe root entry or the sub-directory specifying a parent directory ofsaid file and the information identifying the recording position ofentity data of said file, in said file entry; including the name of thesub-directory specified and the information identifying the root entryor the sub-directory specifying a parent directory of saidsub-directory, in said sub-entry; supervising said entity data recordingarea by identifying the physical format of said entity data recordingarea with the physical format of an effective area of a rewritablememory device capable of re-writing data a plurality of number of times,said rewritable memory device having said effective area and a reservearea for data substitution, said effective area being an area whereentity data is recorded; and supervising said management data byidentifying the physical format of said management data recording areawith the physical format of said reserve area in said rewritable memorydevice.
 62. The recording and/or reproducing apparatus according toclaim 61 wherein said recording and/or reproducing unit divides theentity data recording area and the management data recording area intoblocks, each being a predetermined data unit which is the same as thedata unit of the physical format of the effective area and the reservearea of said rewritable recording medium, and supervises the so dividedentity data recording area and the management data recording area. 63.The recording and/or reproducing apparatus according to claim 62 whereinsaid recording and/or reproducing unit records a file allocation table,a root directory and a sub-directory of the same format as that of thefile management data of the rewritable recording medium, in said entitydata recording area or in the management data recording area; states theconnection sequence of said blocks in said file allocation table; statesan entry, which is the information stating the names of files andsub-directories arranged in an uppermost order directory in ahierarchical directory structure and the recording positions of entitydata of each file and each sub-directory, in said root directory; andstates an entry of the files and the sub-directories, arranged in saidsub-directory, in said sub-directory.
 64. The recording and/orreproducing apparatus according to claim 62 wherein said recordingand/or reproducing unit records, in said entity data recording area orin said management data recording area, the hierarchical directorystructure of a file identified by management data for the write-onceformat, recorded in said management data recording area, and said rootdirectory and the sub-directory supervising the files by the samehierarchical directory structure; said recording and/or reproducing unitalso recording, in said entity data recording area or in said managementdata recording area, a file allocation table stating the connectionsequence of blocks identified by the management data for the write-onceformat recorded in said management data recording area.
 65. Therecording and/or reproducing apparatus according to claim 64 wherein alogical address is recorded in each block of said entity data recordingarea.
 66. The recording and/or reproducing apparatus according to claim65 wherein said recording and/or reproducing unit records only entitydata of one file in one block of said entity data recording area andrecords entity data of one file in one or more blocks formed byconsecutive logical addresses.
 67. The recording and/or reproducingapparatus according to claim 66 wherein said block is formed by aplurality of pages each being of a predetermined data volume.
 68. Therecording and/or reproducing apparatus according to claim 67 wherein amanagement address is set in each page of said management data recordingarea; said recording and/or reproducing unit recording one root entry, asub-entry and a file entry in one page; and wherein said managementaddress is included in said file entry and the sub-entry as theinformation identifying the root entry or the sub-entry of a parentdirectory.
 69. The recording and/or reproducing apparatus according toclaim 67 wherein said recording and/or reproducing unit consecutivelyrecords the root directory, sub-directory and the file entry from one ofthe upper order side and the lower order side of the managementaddresses.
 70. The recording and/or reproducing apparatus according toclaim 69 wherein the recording and/or reproducing unit records the fileallocation table, root directory and the sub-directory, initiallyrecorded on a write-once recording medium, in said entity data recordingarea, and wherein the recording and/or reproducing unit records the fileallocation table, root directory and the sub-directory, recordedupdated, in the management data recording area.
 71. The recording and/orreproducing apparatus according to claim 70 wherein the recording and/orreproducing unit consecutively records the file allocation table, rootdirectory and the sub-directory, recorded updated, from one of the upperorder side and the lower order side of the management addresses oppositeto the side from which the management data for the write-once format isrecorded.
 72. The recording and/or reproducing apparatus according toclaim 71 wherein the recording and/or reproducing unit records thelogical address of the block where the file allocation table, rootdirectory and the sub-directory yet to be updated, are recorded, in ablock where said file allocation table, root directory and thesub-directory are recorded updated.
 73. The recording and/or reproducingapparatus according to claim 72 wherein the recording and/or reproducingunit records a block status flag indicating the fact of deletion of theentity data recorded in a block where the file allocation table, rootdirectory and the sub-directory yet to be updated are recorded.
 74. Therecording and/or reproducing apparatus according to claim 73 wherein,when the file allocation table, root directory or the sub-directory isupdated, the recording and/or reproducing unit records a session anchorindicating the fact of updating in the management data recording areanext to the management data for the write-once format.
 75. The recordingand/or reproducing apparatus according to claim 74 wherein at least twopages of the session anchor are recorded.
 76. The recording and/orreproducing apparatus according to claim 61 wherein said recordingmedium is a write-once non-volatile semiconductor memory.